The three answers above are all good answers…
But the most accurate answer that can be given here, is… Me.
Anyways… Being serious, I’ll now say that I don’t think any one person owns it? Here’s a list of production companies that have been/are involved with it and distributors.
Production Companies:
Kripke Enterprises (as KEI Kripke Enterprises Scrap Metal & Entertainment)
Warner Bros. Television
Wonderland Sound and Vision (in association with)
Supernatural Films
Distributors:
Warner Bros. Television (2005—) (World-wide) (TV)
WB Television Network, The (2005–2006) (USA) (TV) (season 1)
The CW Television Network (The CW) (2006—) (USA) (TV) (season 2—)
AXN (Indonesia) (TV)
Argentina Video Home (2008) (Argentina) (DVD)
DiziMax (Turkey) (TV)
Independent Television (ITV) (2006—) (UK) (TV) (original airing)
Kanal 2 (2008—) (Estonia) (TV)
Net5 (2008—) (Netherlands) (TV)
Network Ten (2007—) (Australia) (TV)
Nippon Television Network (NTV) (2007) (Japan) (TV)
Premiere (2006–2010) (Germany) (TV) (pay-tv) (seasons 1–5)
ProSieben Television (2007—) (Germany) (TV)
RTL Klub Televízió (2006—) (Hungary) (TV) (original airing)
Sky Atlantic HD (2012—) (Germany) (TV) (pay-tv) (season 7—)
Sky Deutschland (2011) (Germany) (TV) (pay-tv) (season 6)
SubTV (2006—) (Finland) (TV)
Super! Drama TV (2007) (Japan) (TV)
TNT (2008–2012) (Turkey) (TV)
TV Norge (2006—) (Norway) (TV)
TV3 Danmark (2006—) (Denmark) (TV)
VT4 (2007—) (Belgium) (TV)
Veronica (2006) (Netherlands) (TV) (season 1) (episodes 1–4)
Viasat3 (2009—) (Hungary) (TV) (repeats)
Warner Home Video (2008—) (Germany) (DVD)
Warner Home Video (2006) (UK) (DVD) (season 1)
Warner Home Video (2007) (UK) (DVD) (season 2)
Warner Home Video (2008) (UK) (DVD) (season 3)
Warner Home Video (2006—) (Japan) (DVD)
Warner Home Video (2007) (Netherlands) (DVD) (seasons 1 and 2)
Warner Home Video (2013) (Netherlands) (DVD) (seasons 7 and 8)
Warner Home Video (2014) (Netherlands) (DVD) (season 9)
Warner Home Video (2015) (Netherlands) (DVD) (season 10)
Warner Home Video (2016) (Netherlands) (DVD) (season 11)
Warner Home Video (2006) (USA) (DVD) (season 1)
Warner Home Video (2007) (USA) (DVD) (season 2)
Warner Home Video (2008) (USA) (DVD) (season 3)
Warner Home Video (2009) (USA) (Blu-ray) (DVD) (season 4)
Warner Home Video (2009) (USA) (DVD) (season 4)
Österreichischer Rundfunk (ORF) (2009—) (Austria) (TV) (ORF1)